Lipophilic acyclic dibenzopolyether diamides, 12 kinds, have been designed to prepare solvent polymeric membrane ion-selective electrodes (ISEs) for Pb+2. The ionophores include 1,5-bis[2-(N,N-dialkylcarbamoylmethoxy)phenoxy]-3-oxapentanes 1-4, 1,5-bis[2-(N,N-dialkylcarbamoylpentadecyloxy)phenoxy]-3-oxapentanes 5-8, and 1,2-bis[2-(2'-N,N-dialkylcarbamoylpentadecyloxy)phenoxy]ethanes 9 12. Linear response concentration range of the ISE based on 9 is 3 x 10-2 - 1 x 10-6 M of Pb2+ (average slope = 28.5 mV decade-1). Potentiometric selectivities of the ISEs based on 1-12 for Pb2+ over other heavy metal cations, alkali metal cations, and alkaline earth metal cations have been assessed. These ISEs exhibit remarkably high selectivities for Pb2+ relative to heavy metal cations, such as Cu2+, Fe2+, and Ni2+, the selectivity coefficients (K(Pb.Cu)/(Pot)) being 5 x 10-5 - 6 x 10-5 - for 1-4 and ca. 6 x 10-4 - for 9. For the Pb2+ selectivities over alkali metal cations, such as Na+ and K+, 9 which has an ethylene glycol spacer and a N,N-diethyl group is superior to other dibenzopolyether diamide ionophores 1-8 and 10-12.
- Acyclic dibenzopolyether diamides
- Lead-selective ionophore
- Poly(vinyl chloride) membrane
ASJC Scopus subject areas
- Analytical Chemistry